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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Cruise-dash optimization applied to an air-breathing missile

Chichka, David F. January 1985 (has links)
The method of singular perturbations is applied to the determination of the optimal range-fuel-time trajectory for an air-breathing missile. This method is shown to lead to the reduced-order "cruise-dash" model, and this model is used in the optimization study. Earlier work in this area is extended by the inclusion of two not heretofore considered limits on the dynamical system. The results of the earlier work are shown to hold throughout much of the velocity regime in which the missile operates, but operation in the very high and very low velocity ranges is shown to be sharply curtailed, with the optimal operating points being changed drastically in some cases. Also, the effect of the non-zero minimum admissible throttle setting and the resultant throttle-chattering on the solution of the control problem is examined in some detail. / M.S.
72

Two-period, stochastic, supply-chain models with recourse for naval surface warfare

Avital, Ittai 03 1900 (has links)
Approved for public release; distribution is unlimited. / We model the minimum-cost procurement and allocation of anti-ship cruise missiles to naval combat ships as a two-period stochastic integer program. Discrete scenarios in two periods define "demands" for missiles (i.e., targets and number of missiles required to kill those targets), which must be met with sufficiently high probabilities. After the former combat period, ships may replenish their inventories from a depot if desired and if the available depot inventory suffices. A force commander optimizes ship-to-target assignments to meet demands. The basic model solves slowly, so we add constraints to enforce reasonable operational directives, and add valid inequalities. These improvements reduce the solution time by 95% for the test case. Instances with up to six ships and five scenarios in each period then solve in less than one hour on a 2 GHz personal computer. / Lieutenant Commander, Israel Navy
73

Electronic attack and sensor fusion techniques for boot-phase defense against multiple ballistic threat missiles

Yildiz, Kursad 06 1900 (has links)
The first objective of this thesis is to investigate the effect of several forms of electronic attack (EA) on the radio frequency (RF) sensors used within a boost-phase ballistic missile intercept system. The EA types examined include noise jamming, chaff, radar cross section (RCS) reduction, and expendable decoys. Effects of the EA methods are evaluated by examining the track position error at the sensor fusion output. Sensor fusion architectures investigated include a weighted average sensor fusion; Kalman-filter-based sensor fusion, and joint probabilistic data fusion architecture. A second objective of this thesis is to extend the single-target, single-interceptor analysis and simulation to a multi-target, multi-interceptor scenario to include the formation of an ellipsoidal gating process to correctly correlate the target measurements with the corresponding track file. We show that the most effective EA is the use of noise jamming followed by a RCS reduction of the missile body. We also show that a properly designed sensor fusion process can effectively mitigate the EA techniques that might be used in a boostphase intercept scenario.
74

From Rogue to Vogue : why did Libya give up its weapons of mass destruction?

McFall, Joseph D. 09 1900 (has links)
This thesis analyzes Libya's historic 2003 decision to abandon its weapons of mass destruction (WMD) programs. In the 2 years following the decision, several theories have emerged to explain why the Libyan regime renounced these dangerous weapons. The author uses current literature and relevant sources to analyze the three most probable external causal factors: sanctions and diplomacy, intelligence, and coercive diplomacy. He finds that sanctions, diplomacy, and intelligence were significant in altering the Libyan cost-benefit analysis in favor of the West. These findings have political and theoretical implications. Lessons learned from the Libyan case will not be effective against Iran and North Korea due to differences between these countries' proliferation motivation levels and the Libyan case. However, the influence strategies that were effective against Libya are likely to be applicable in other situations. The author finds that more research is still needed to identify the conditions when different strategies are most likely to be effective.
75

Detection and jamming low probability of intercept (LPI) radars

Denk, Aytug. 09 1900 (has links)
An increasing number of LPI radars are integrated into integrated air defense systems (IADS) and modern platforms and weapons, such as anti-ship missiles, and littoral weapon systems. These LPI radars create a requirement for modern armed forces to develop new techniques, strategies, and equipment. The primary objective of this thesis is to investigate methods and means to counter LPI radar threats integrated into a modern platforms and weapons and focus on the related techniques, strategies, and technology. To accomplish this objective both platform centric and network centric approaches will be examined thoroughly.
76

Hermite-Gaussian modes and mirror distortions in the free electron laser

Vigil, Ricardo. 06 1900 (has links)
The free electron laser (FEL) is proposed to meet the Navy's need for a speed-of-light high energy laser weapon capable of engaging a variety of targets including anti-ship cruise missiles, small boats, and theater ballistic missiles. A key attribute of FELs is good optical beam quality; in other words, they operate in only a few of the lowest-order transverse Gaussian modes. For weapons applications, a good mode quality is desired because it delivers the highest intensity on target ensuring a high level of lethality. A few higher-order modes can arise from the interaction of the electron beam with the optical beam, or from misalignments of the electron beam or resonator mirrors. High intensity on FEL optics can lead to mirror distortion due to heating and insufficient cooling of the mirror substrate. Mirror distortions, including astigmatism, can cause higher-order modes to appear affecting FEL performance. Therefore, it is important to quantify these higher-order modes because doing so uniquely identifies the optical field and may allow for corrective optics to single out the best modes for FEL lethality. This thesis will review free electron laser theory, and for the first time develop analytical solutions to quantify Hermite-Gaussian higher-order modes, develop a diagnostic for modal analysis, and determine the tolerance limits on mirror distortions.
77

High-power amplifier free electron lasers

Voughs, Tyrone Y. 06 1900 (has links)
The free electron laser (FEL) is among the latest technologies of interest to the U.S. military, in particular, the Navy. In naval applications, FEL laser would serve as a self-defense weapon system, protecting the ship from an array of threats including anti-surface cruise missiles and small boats. This system's potential range and deep magazine makes it ideal as point defense against incoming missiles. Its inexpensive cost of only a few dollars per engagement and multi-mission capability makes this future weapon system superior to the short-range missile-defense systems employed today. The most powerful FEL is currently located in Jefferson Lab, operating at 10 kW, two orders of magnitude short of the 1 MW power level required for weapons application. This thesis will describe the components and theory of operation of the FEL, as well as analyze two competing designs for the next step in the evolution of the future weapon system, the 100 kW FEL, proposed by Brookhaven and Los Alamos National Labs. Due to advances in NPS simulation techniques for the amplifier configuration, a more in depth analysis including the effects of electron beam tilt and shift is performed for the first time on these proposed designs.
78

Application of the Janus Combat Model for analysis of alternatives : a study of the operational effectiveness of the common missile as compared to the Hellfire /

Vannoy, John M. January 2002 (has links) (PDF)
Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Bard K. Mansager, Scott T. Crino, Keith Snider. Includes bibliographical references (p. 105-107). Also available online.
79

Is Saudi Arabia a nuclear threat? /

McDowell, Steven R. January 2003 (has links) (PDF)
Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, September 2003. / Thesis advisor(s): James Russell, Peter R. Lavoy. Includes bibliographical references (p. 69-79). Also available online.
80

An electro-optical tracking system

Harrison, Irene Roberta, 1952- January 1976 (has links)
No description available.

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